_ 
( Texliv: 4 
laterally, and so widen and again contract the space contained 
between them (e. g. during the passage between them of an egg 
for which they have helped to form a nidus.) 5,—They can, 
however, do, and even must, take a part, which may be called 
independent, in performing the processes of excavation and 
oviposition. Their mere form compels them to act as does a 
wedge, and their special armature in particular cases involves 
their performance of various other functions, which may be 
summed up in the general phrase, ‘laceration of the tissues 
through which they travel.” 6,—The so-called “saws”’ have 
separate motions of their own, independent of such as are 
communicated to them by the supports. These movements 
are limited, however, to sliding backwards and forwards, 
along the lower margins of the supports, to such an extent as 
their attachment to the abdomen permits. And these are the 
only movements made by them, wnless the supports move also, 
7.—The entire process is the work of the scalpellum as a 
whole ; the characters indicating its wedge-like action reside 
mainly in the “supports”; those which entitle it to be 
called in any sense a ‘“‘saw” must be sought in the lower 
margins of the so-called “saws proper,” those which enable it 
to act as a “rasp” or “comb,” partly in the sides and back 
of the supports, and partly in the sides of the saws. 
And now, to the few detailed records of observations on the 
operation as performed by the living insects which are vouched 
for by their authors as witnessed by themselves—and it is 
surprising how few they are; in fact, I can only cite three 
such records, those of Vallisnieri, Réaumur, and Newport, 
though I dare not deny that others may have escaped my 
notice—however, to these few signed affidavits of eye-witnesses 
1 will add another of my own. 
In the summer of 1910 I was enabled through the great 
kindness of a correspondent—Miss Ethel Chawner, of Lynd- 
hurst, who has long studied the habits of these insects and 
immensely increased our knowledge of them, and who (I am 
pleased to add) is a Fellow of this Society—to observe the 
phenomenon repeatedly in the case of a species, viz. Phymato- 
cera aterrima, Klug, whose particular method of operating, and 
the nature of the material on which (by preference) it works, 
